This study is a comparison of two doses of dapsone as PCP prophylaxis in HIV-infected infants and children who are intolerant to trimethoprim-sulfamethoxazole (TMP-SMX). The primary objectives are to compare the toxicity of daily vs. weekly dapsone in HIV-infected infants and children and to study the pharmacokinetics of orally administered dapsone in HIV-infected infants and children.